1. Field of the Invention
The present invention relates to a method and an apparatus for forming metallic materials.
2. Description of the Related Art
Various methods of forging metallic materials at high temperatures have been known. In a typical hot-forging process, the metallic material is heated by a suitable method, such as induction-heating, is conveyed to the dies, and is forged by the dies. In this process, the temperatures of the metallic material and the dies are not controlled precisely, and the condition of the forged metallic material thus can not be controlled. Therefore, the forged material must be heat-treated to control the metallic structure and/or the mechanical properties of the material.
In addition, in the conventional hot-forging process, the atmosphere is not controlled. Thus, the surface of the forged material is oxidized, and must be descaled.
Accordingly, it is an object of the present invention to provide a method of forming a metallic material that enables precise temperature control of the metallic material.
The second object of the present invention is to provide a method of forming a metallic material that avoids formation of undesirable surface layer, such as oxidized layer.
The third object of the present invention is to provide an apparatus capable of executing the above methods.
To achieve the above objectives, the present invention provides a method of forming a metallic material, the method including the steps of: placing a metallic material between dies; heating the metallic material together with the dies; and forming the metallic material by using the dies.
Preferably, the heating step is carried out by irradiating thermal radiation to the metallic material and the dies, by means of a heater being arranged remote from the metallic material and the dies. In a specific embodiment, the heater comprises a plurality of infrared lamps.
Preferably, in the heating step and the forming step, an inert gas atmosphere is established around the metallic material and the dies.
Alternatively, an evacuated atmosphere may be established instead of the inert gas atmosphere.
The method may further include the step of: cooling, after the forming step, the metallic material and the dies by using the inert gas; and removing, after the cooling step, the metallic material from the dies. In the cooling step, the inert gas atmosphere or the evacuated atmosphere is preferably maintained.
The present invention also provides a forming apparatus, which includes: first and second die supports each adapted to retain a die for forming a metallic material; a drive that causes relative movement between the die supports to form the metallic material; and a heater adapted to heat the dies together with the metallic material.
In one embodiment, the above heater is configured to irradiate thermal radiation and is arranged remote from the metallic material and the dies. In a specific embodiment, the heater comprises a plurality of infrared lamps arranged around the metallic material and the dies.
In a specific embodiment, the apparatus is provided with an enclosure adapted to surround the dies to form a forming chamber in which the metallic material is formed. The enclosure is transmissive to the thermal radiation.
The apparatus is preferably provided with an inert gas feeder that supplies an inert gas into the processing chamber. In a specific embodiment, the die support is provided with a gas passage, through which the inert gas is fed to the dies.